Question

How to declare and initialize 1D (one dimensional) int array in C

Answer 1

#include <stdio.h>
 
#define SIZE 3
#define LEN 5

void print(int arr[], int len);
 
int main(void)
{
    int n1[] = {1, 2, 3}; 
    int n2[4] = {1, 2, 3};
    int n3[3] = {0};
    int n4[SIZE] = {1, 2, 3};
    int n5[6] = {[4] = 13, [0] = 1, 2, 3, 4};
    int n6[LEN] = { 1, 3, 5, 7, 9, [LEN - 4] = 2, 4, 6, 8, 0};
    int n7[15] = { 1, 3, 5, 7, 9, [LEN - 3] = 2, 4, 6, 8, 0};
    
    print(n1, sizeof n1 / sizeof(int));
    print(n2, sizeof n2 / sizeof(int));
    print(n3, sizeof n3 / sizeof(int));
    print(n4, sizeof n4 / sizeof(int));
    print(n5, sizeof n5 / sizeof(int));
    print(n6, sizeof n6 / sizeof(int));
    print(n7, sizeof n7 / sizeof(int));
    
    return 0;
}

void print(int arr[], int len)
{
    for (int i = 0; i < len; i++)
        printf("%d ", arr[i]);
        
    printf("\n");
}

 
/*
run:

1 2 3
1 2 3 0
0 0 0
1 2 3
1 2 3 4 13 0
1 2 4 6 8
1 3 2 4 6 8 0 0 0 0 0 0 0 0 0

*/

 

70+ SQL courses for beginners and professionals

Answer 2

#include <stdio.h>
  
void print(int arr[], int len);
  
int main(void)
{
    int n = 1;
    int arr[3] = {n++, n++};
     
    print(arr, sizeof arr / sizeof(int));
     
    return 0;
}
 
void print(int arr[], int len)
{
    for (int i = 0; i < len; i++)
        printf("%d ", arr[i]);
         
    printf("\n");
}
 
  
/*
run:
 
1 2 0
 
*/

 

70+ SQL courses for beginners and professionals

Answer 3

#include <stdio.h>
  
void print(int arr[], int len);
  
int main(void)
{
    int arr[3] = {};
     
    print(arr, sizeof arr / sizeof(int));
     
    return 0;
}
 
void print(int arr[], int len)
{
    for (int i = 0; i < len; i++)
        printf("%d ", arr[i]);
         
    printf("\n");
}
 
  
/*
run:
 
0 0 0

*/

 

70+ SQL courses for beginners and professionals